In a disaster recovery technical environment for a storage system, there might exist multiple File level remote replication sessions, which replicate data from an active storage site to a standby storage site. While the data keeps growing, a storage pool such as the NAS User-defined pool protected by this remote replication session nearly reaches its space limit. Therefore, when the storage pool of the active storage site is close to its space limit, it is necessary to extend the space of the storage pool and desire to keep the remote replication session functioning while extending the space of the storage pool.
In approaches in the prior art, it is necessary to first delete existing replication session on the storage pool, then extend the storage pool on both active and standby storage sites, and then re-create the replication session. Since it may take days or even weeks for a synchronization process of a new replication session after its creation, after the previous replication session is deleted and before the new replication session is synchronized, there is no protection on user data for a rather long time period. If a disaster happens during this phase, there will be data loss.